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In vitro activity of amikacin against isolates of Mycobacterium avium complex with proposed MIC breakpoints and finding of a 16S rRNA gene mutation in treated isolates.

Publication ,  Journal Article
Brown-Elliott, BA; Iakhiaeva, E; Griffith, DE; Woods, GL; Stout, JE; Wolfe, CR; Turenne, CY; Wallace, RJ
Published in: J Clin Microbiol
October 2013

Amikacin is a major drug used for the treatment of Mycobacterium avium complex (MAC) disease, but standard laboratory guidelines for susceptibility testing are not available. This study presents in vitro amikacin MICs for 462 consecutive clinical isolates of the MAC using a broth microdilution assay. Approximately 50% of isolates had amikacin MICs of 8 μg/ml, and 86% had MICs of ≤16 μg/ml. Of the eight isolates (1.7%) with MICs of 64 μg/ml, five had an MIC of 32 μg/ml on repeat testing. Ten isolates (2.1%) had an initial amikacin MIC of >64 μg/ml, of which seven (1.5%) had MICs of >64 μg/ml on repeat testing. These seven isolates had a 16S rRNA gene A1408G mutation and included M. avium, Mycobacterium intracellulare, and Mycobacterium chimaera. Clinical data were available for five of these seven isolates, all of which had received prolonged (>6 months) prior therapy, with four that were known to be treated with amikacin. The 16S mutation was not detected in isolates with MICs of ≤64 μg/ml. We recommend primary testing of amikacin against isolates of the MAC and propose MIC guidelines for breakpoints that are identical to the CLSI guidelines for Mycobacterium abscessus: ≤16 μg/ml for susceptible, 32 μg/ml for intermediate, and ≥64 μg/ml for resistant. If considered and approved by the CLSI, this will be only the second drug recommended for primary susceptibility testing against the MAC and should facilitate its use for both intravenous and inhaled drug therapies.

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Published In

J Clin Microbiol

DOI

EISSN

1098-660X

Publication Date

October 2013

Volume

51

Issue

10

Start / End Page

3389 / 3394

Location

United States

Related Subject Headings

  • RNA, Ribosomal, 16S
  • Point Mutation
  • Mycobacterium avium-intracellulare Infection
  • Mycobacterium avium Complex
  • Middle Aged
  • Microbiology
  • Microbial Sensitivity Tests
  • Humans
  • Female
  • Drug Resistance, Bacterial
 

Citation

APA
Chicago
ICMJE
MLA
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Brown-Elliott, B. A., Iakhiaeva, E., Griffith, D. E., Woods, G. L., Stout, J. E., Wolfe, C. R., … Wallace, R. J. (2013). In vitro activity of amikacin against isolates of Mycobacterium avium complex with proposed MIC breakpoints and finding of a 16S rRNA gene mutation in treated isolates. J Clin Microbiol, 51(10), 3389–3394. https://doi.org/10.1128/JCM.01612-13
Brown-Elliott, Barbara A., Elena Iakhiaeva, David E. Griffith, Gail L. Woods, Jason E. Stout, Cameron R. Wolfe, Christine Y. Turenne, and Richard J. Wallace. “In vitro activity of amikacin against isolates of Mycobacterium avium complex with proposed MIC breakpoints and finding of a 16S rRNA gene mutation in treated isolates.J Clin Microbiol 51, no. 10 (October 2013): 3389–94. https://doi.org/10.1128/JCM.01612-13.
Brown-Elliott BA, Iakhiaeva E, Griffith DE, Woods GL, Stout JE, Wolfe CR, et al. In vitro activity of amikacin against isolates of Mycobacterium avium complex with proposed MIC breakpoints and finding of a 16S rRNA gene mutation in treated isolates. J Clin Microbiol. 2013 Oct;51(10):3389–94.
Brown-Elliott, Barbara A., et al. “In vitro activity of amikacin against isolates of Mycobacterium avium complex with proposed MIC breakpoints and finding of a 16S rRNA gene mutation in treated isolates.J Clin Microbiol, vol. 51, no. 10, Oct. 2013, pp. 3389–94. Pubmed, doi:10.1128/JCM.01612-13.
Brown-Elliott BA, Iakhiaeva E, Griffith DE, Woods GL, Stout JE, Wolfe CR, Turenne CY, Wallace RJ. In vitro activity of amikacin against isolates of Mycobacterium avium complex with proposed MIC breakpoints and finding of a 16S rRNA gene mutation in treated isolates. J Clin Microbiol. 2013 Oct;51(10):3389–3394.

Published In

J Clin Microbiol

DOI

EISSN

1098-660X

Publication Date

October 2013

Volume

51

Issue

10

Start / End Page

3389 / 3394

Location

United States

Related Subject Headings

  • RNA, Ribosomal, 16S
  • Point Mutation
  • Mycobacterium avium-intracellulare Infection
  • Mycobacterium avium Complex
  • Middle Aged
  • Microbiology
  • Microbial Sensitivity Tests
  • Humans
  • Female
  • Drug Resistance, Bacterial